In general, a filtering apparatus for filtering raw water containing pollutants, such as various impurities, mixtures, or the like, or mixed materials into clear purified/treated water, has a membrane filter (hereinafter, referred to as “membrane”) having many minute pores.
Therefore, if the raw water containing various pollutants flows into the filtering apparatus, the polluted raw water is purified by passing through the membrane installed within the filtering apparatus and various pollutants failing to passing through the membrane are accumulated and concentrated in the membrane, however, if the density of concentrated pollutants reaches certain amount, the water containing pollutants are discharged to the concentrated water outlet by a separate signal system.
The pollutants accumulated and concentrated in the membrane block the pores of the membrane so as to deteriorate the purification performance of the membrane in certain periods, thereby causing a need for replacement. Therefore, a provision for removing the pollutants deposited in the membrane is installed in the membrane in such a manner that the filtering performance of the membrane can be maintained for a long time.
In the apparatus for removing the pollutants deposited in the membrane and maintaining the filtering performance, a variety of technologies has been disclosed. Among these technologies, the applicant's related work, “Closed-type waste water treatment apparatus employing ultrasonic vibrator” is disclosed in Korean patent publication No. 10-2007-0106192, published Nov. 1, 2007, which is hereby incorporated by reference in its entirety.
The following is a brief summary of the applicant's related work.
If the raw water containing the pollutants inflows, pure water contained in the polluted raw water passes and is filtered through the pores of a membrane, filtered purified/treated water is discharged to a purified/treated water outlet, and the raw water containing the pollutants is concentrated for predetermined periods so as to be discharged to a concentrated water outlet. Further, the impurities adhere to the pores of the membrane due to filtering the raw water containing the pollutants receives the power (energy, shearing stresses) of the vortex generated by the rotation of a vortex generation rotor installed in a driving shaft, so that the vortex prevents the impurities from blocking the pores, thereby maintaining the filtering performance.
As illustrated in FIG. 8 and FIG. 9, the conventional filtering apparatus 50 consists of a barrel 51 having a closed space within, a plurality of membranes 52 installed in an inner wall of the barrel 51 to filter the pollutant, a vortex generation rotor 55 alternatively arranged with the membranes and installed by a rotary shaft 54 rotated by a driving motor 53 to generate vortex to be rotated with the rotary shaft 54, a raw water inlet 56 through which raw water containing impurities is introduced into the barrel 51, a purified water outlet 57 through which treated water filtered by the membranes is discharged, and a concentrated water outlet 58 through which the water containing various pollutants failing to passing through the membrane 52 and accumulated and concentrated in the barrel 51 is discharged.
In the filtering apparatus 50 of state of the art, the rotary shaft 54 is rotated by the driving motor 53 when raw water containing various impurities inflows to a raw water inlet 56. The vortex generation rotors 55 are rotated by the rotary shaft 54 and stir the raw water so as to remove the solid matter, such as impurities, or the like, deposited on the surfaces of the membranes 52 in order to maximize the functionality of the membranes 52.
Moreover, if the raw water continues to flow into the barrel 51, the various pollutants failing to passing through the membrane are accumulated and concentrated in the membrane for predetermined periods so as to be discharged to the outside.
As mentioned above, the shape of the filtering apparatus 50 of state of the art is formed to be installed perpendicular to the ground so that the filtering apparatus 50 of perpendicular shape has to be formed under certain fixed height. It is because there will be limitation of height in the place to be installed, impossible to install as duplex structure for large scale installation, or possibility for falling down if the filtering apparatus 50 is installed too high.
Another problem of the said filtering apparatus 50 is that if the filtering apparatus is installed in certain height and the diameter of the vortex generation rotor 55 is set to be over certain size in order to form in large scale, the diameter of the membranes 52 or the rotors 55 becomes large so that the membranes 52 or the rotors 55 become over weight. Therefore, the membranes 52 or the rotors 55 can be bent or drooped so as to deteriorate the filtering functionality and consequently there will be limitations to form large scales of filtering apparatus.
Moreover, there is another problem of the filtering apparatus that the diameter of the rotor 55 installed around the raw water inlet 56 and the diameter of the rotor installed around the concentrated water outlet where the density of concentrated water is maximized are the same. That is, it is not necessary to waste the driving power by having the same size for the rotors of raw water inlet 56 and concentrated water outlet 58 because the pollution density of raw water in the raw water inlet 56 is much lower than in the concentrated water outlet 58. Thus, it is waste of power to collectively operate the driving motor with the same intensity and it is not necessary to have the same size for rotors in raw water inlet and outlet. The reason that the density of raw water becomes higher in the concentrated water outlet 58 than in the raw water inlet 56 is because the raw water is filtered one by one from the membranes 52 and pure water is discharged.